1. Field of the Invention
The present invention relates to: a thin film suitable for use as an electronic part; a method and an apparatus for forming the thin film; and an electronic component incorporating the thin film.
2. Description of the Related Art
Thin films have a very wide role in today""s society and are applied to various kinds of daily products such as wrapping paper, magnetic tape, capacitors or semiconductors. Without these thin films, current high performance or size reducing technology could not be achieved.
Methods for producing thin films that satisfy industrial demands have been undergoing various developments, for example, thin films earmarked for wrapping paper, magnetic tape, capacitors, etc., are produced by combining a vacuum vapor deposition process with a sequential rolling process which is considered to have an advantage in high-speed mass production. In such a method, a material to be deposited (hereinafter, simply referred to as a xe2x80x9cdeposition materialxe2x80x9d) and a material as a base substrate where the deposition material is deposited are selected depending on the use of the thin film. When necessary, reaction gas may be introduced into a vacuum chamber or the base substrate may be provided with an electric potential in order to form a thin film with the desired characteristics.
A magnetic recording medium with long length can be obtained by using a deposition material containing magnetic elements (e.g., Co, Ni or Fe) and performing reaction deposition while introducing an oxygen gas into the vacuum chamber. In the case of a semiconductor, a sputtering method is generally used.
A thin film made of resin is formed by a coating method. Reverse coating or die coating is industrially employed as a method for providing a coating of resin on the base substrate. Generally, a material is diluted with a solvent before being coated, dried and cured on the base substrate. By a usual coating method, the thickness of the coating material deposited is generally several microns or more. Therefore, in order to form an extremely sheer resin thin film (herein, a xe2x80x9csheerxe2x80x9d resin thin film refers to a xe2x80x9cthinxe2x80x9d resin thin film), the coating material needs to be diluted with a solvent. The lowest limit of the thickness of the resin thin films formed by the above-described methods is, in most of the cases, around 1 xcexcm. Even when the coating material is diluted with the solvent, a resin thin film with a thickness of 1 xcexcm or less is hard to obtain. Additionally, dilution with a solvent tends to cause defects in the dried coating film and is associated with other problems including environmental problems.
Recently, various composite thin films made from laminated thin films of different kinds have become available and have been used in various industrial fields. An application of composite thin films as chip-shaped electronic components has been receiving much attention. The composite thin films allow for the size reduction of, while still maintaining a high performance, for example, capacitors, coils, resistors or combined components thereof and have already been produced and the market for such products is expanding.
As described above, various methods are available for forming resin thin films. However, by the general coating method, the thickness of the coating material would be several microns or more at the thinnest. Therefore, in order to form an extremely sheer resin thin film, the coating material needs to be diluted with a solvent. Even when the coating material is diluted with a solvent, a resin thin film with a thickness of 1 xcexcm or less is hard to obtain. Additionally, dilution with a solvent tends to cause defects in the dried coating film and is associated with other problems including environmental problems.
In the case of a laminate film, adhesion between the film layers is important as well as the performance of each film layer. Insufficient adhesion between the film layers will cause a minor separation between the film layers during subsequent production steps or during actual usage. Such a minor separation often results in separation of the entire adhesion area between the film layers. Therefore, from a practical standpoint, such a problem needs to be solved.
According to one aspect of the present invention, a method for forming a thin film includes the steps of: supplying a deposition material in the form of a liquid onto a heated surface; heating and vaporizing the deposition material on the heated surface while the deposition material is undergoing movement; and depositing the deposition material onto a deposition surface. The deposition material is supplied onto a position of the heated surface where the vaporized deposition material does not reach the deposition surface.
In one embodiment of the present invention, the deposition material on the heated surface is carried in accordance with a rotational movement of the heated surface.
In another embodiment of the present invention, the step of supplying the deposition material in the form of a liquid onto the heated surface includes a step of supplying the deposition material in either an atomized state or a vaporized state.
In still another embodiment of the present invention, the step of supplying the deposition material includes one of the steps of: ultrasonic atomizing; spraying atomizing; mechanical atomizing; and evaporating.
In yet still another embodiment of the present invention, the step of supplying the deposition material, the step of heating and vaporizing and the step of depositing the deposition material onto the deposition surface are conducted in a vacuum state.
In still another embodiment of the present invention, the deposition material is a curable resin material. The method further includes, following the step of depositing the deposition material onto the deposition surface, a step of curing the deposited deposition material.
In still another embodiment of the present invention, the method further includes a step of forming another layer made of a material different from the deposition material on a resin thin film made from the cured deposition material.
In still another embodiment of the present invention, the step of supplying the deposition material is conducted in a vacuum state that is different from a vacuum state for the step of curing the deposited deposition material and the step of forming another layer made of the material different from the deposition material on the resin thin film made from the cured deposition material.
In still another embodiment of the present invention, the method includes a step of alternately conducting a step of forming the resin thin film and a step of forming another layer.
In still another embodiment of the present invention, the deposition material on the heated surf ace is carried by running the deposition material along the heated surface.
In still another embodiment of the present invention, the method includes a step of running the deposition material on a plurality of heated surfaces, said heated surfaces being at different temperatures.
In still another embodiment of the present invention, a region of the heated surface where the deposition material in the form of a liquid is supplied is maintained at a lower temperature than a temperature of other regions of the heated surface.
In still another embodiment of the present invention, the deposition material moves in the form of a liquid on the plurality of heated surfaces.
In still another embodiment of the present invention, the method further includes the steps of: supplying the deposition material on the heated surface undergoing rotational movement; and carrying the deposition material by rotating the heated surface.
In still another embodiment of the present invention, the method further includes a step of collecting part of the deposition material in the form of a liquid that is carried along the heated surface of a container.
According to another aspect of the present invention, the method for forming a thin film includes a step of depositing a deposition material onto a deposition surface. The method further includes, prior to depositing the deposition material onto the deposition surface, a step of radiating a charged particle beam onto at least one of the deposition material or the deposition surface.
In one embodiment of the present invention, the step of depositing the deposition material on the deposition surface includes a step of depositing at least one of the deposition material which is in either an atomized state or a vaporized state, onto the deposition surface.
In another embodiment, the step of depositing includes one of the steps of: ultrasonic atomizing; spraying atomizing; mechanical atomizing; and evaporating.
In still another embodiment, the step of evaporating includes a step of supplying the deposition material in the form of a liquid to the heated surface, and the step of supplying the deposition material is a step of supplying the deposition material which is in either an atomized state or a vaporized state, onto the deposition surface.
In yet still another embodiment of the present invention, the charged particle beam includes at least one of an electron beam or an ion beam.
In still another embodiment of the present invention, an acceleration voltage of the charged particle beam is about 50 V or more.
In still another embodiment of the present invention, the deposition material is a curable resin material. The method further includes, following the step of depositing the deposition material onto the deposition surface, a step of curing the deposited deposition material.
In still another embodiment of the present invention, a viscosity of the curable resin material at a normal temperature and a normal pressure is in a range of about 30 cps to about 800 cps.
In still another embodiment of the present invention, the step of depositing the deposition material onto the deposition surface and the step of radiating the charged particle beam are conducted in different vacuum states.
According to another aspect of the present invention, a method for forming a resin thin film and a metal thin film under a vacuum condition includes the steps of: forming the resin thin film; performing a discharge treatment by exposing the resin thin film to a discharge atmosphere containing oxygen gas; and forming the metal thin film on the resin thin film.
In one embodiment of the present invention, the step of forming the resin thin film, the step of performing the discharge treatment and the step of forming the metal thin film are sequentially conducted in a vacuum atmosphere.
In another aspect of the present invention, a method for forming a resin thin film and a metal thin film includes the steps of: depositing an ultraviolet curable resin; forming the cured resin thin film which is incompletely cured by radiating ultraviolet light onto the ultraviolet curable resin in a atmosphere containing oxygen gas; and forming the metal thin film on the resin thin film.
In one embodiment of the present invention, the step of forming the metal thin film is conducted by employing an electron beam deposition method.
In another embodiment of the present invention, the step of forming the metal thin film includes a step of depositing a metal thin film while radiating an electron beam onto the resin thin film.
In another embodiment of the present invention, the ultraviolet curable resin includes an acrylic-type resin.
In another embodiment of the present invention, the method further includes a step of alternately conducting a step of forming the resin thin film and a step of forming the metal thin film.
According to another aspect of the present invention, a thin film formation apparatus includes: a heater having a heated surface for heating and vaporizing a deposition material while carrying the deposition material; a supplier which supplies the deposition material to the heated surface; a support body which maintains a substrate with a deposition surface such that the deposition material which is vaporized is deposited onto the deposition surface; and a curing device which cures the deposition material on the deposition surface. The deposition material is supplied at a position of the heated surface where the vaporized deposition material does not reach the deposition surface.
In one embodiment of the present invention, the heater includes the heated surface which rotates and carries the deposition material supplied to the heated surface at a position where the deposition material, when vaporized, directly reaches the deposition surface.
In another embodiment of the present invention, the heater is a heated roller having the heated surface.
In still another embodiment of the present invention, the heater is a heated belt having the heated surface.
In yet still another embodiment of the present invention, the film formation apparatus further includes a supplier for supplying the deposition material which is in either an atomized state or a vaporized state, to the prescribed position.
In still another embodiment of the present invention, the supplier includes one of an ultrasonic atomizing device; a spray atomizing device; a mechanical atomizing device; and an evaporating device.
In still another embodiment of the present invention, the heated surface of the heater is tilted so that the deposition material supplied to the heated surface flows, the deposition material being heated and vaporized while moving thereon.
In still another embodiment of the present invention, the film formation apparatus further includes an obstruction wall between the position where the deposition material is supplied to the heated surface and the deposition surface, so that the deposition material is prevented from reaching the deposition surface in a linear manner.
In still another embodiment of the present invention, the film formation apparatus further includes a second heater, the second heater having a first heated surface which rotates and receives the deposition material on the first heated surface from the heater and heats and vaporizes the deposition material while carrying the deposition material.
In still another embodiment of the present invention, the other heater includes at least one of a heated roller having a heated surface and a heated belt having a heated surface.
In still another embodiment of the present invention, the thin film formation apparatus further includes a container for collecting the deposition material.
In still another embodiment of the present invention, the thin film formation apparatus further includes a vacuum chamber. The vacuum chamber has the heater, the support body and the curing device, the supplier supplies the deposition material to the heated surface of the heater from outside of the vacuum chamber.
In still another embodiment of the present invention, the curing device includes at least one of a UV light radiation device, an electron beam radiation device and a thermosetting device.
In still another embodiment of the present invention, the curing device includes a UV light radiation device and an oxygen gas inlet provided in the UV light radiation device.
According to another aspect of the present invention, a thin film formation apparatus includes: a first supplier which supplies a deposition material that is atomized or vaporized; a support body which maintains a substrate with a deposition surface such that the deposition material which is atomized or vaporized is deposited onto the deposition surface; and a device for radiating a charged particle beam onto at least one of the deposition material and the deposition surface.
In one embodiment of the present invention, the first supplier includes one of an ultrasonic atomizing device; a spray atomizing device; a mechanical atomizing device; and an evaporating device.
In another embodiment of the present invention, the thin film formation apparatus having the first supplier with the heated surface for vaporizing the deposition material further includes a second supplier supplying at least one of the deposition material which is atomized and the deposition material which is vaporized on the heated surface of the first supplier.
In still another embodiment of the present invention, the charged particle radiation device includes at least one of an electron beam radiation device and an ion beam radiation device.
In yet still another embodiment of the present invention, the thin film formation apparatus further includes a curing device for curing the deposition material deposited on the deposition surface, the curing device having at least one of an UV light radiation device, an electron radiation device and a thermosetting device.
According to another aspect of the present invention, a thin film formation apparatus for continuously forming a resin thin film and a metal thin film in a vacuum state is provided. The surface of the resin thin film is exposed to discharge atmosphere containing oxygen gas after the resin thin film is formed.
According to another aspect of the present invention, a thin film formation apparatus for continuously forming a resin thin film and a metal thin film in a vacuum state, includes a UV light radiation device for radiating the surface of the resin thin film with UV light in atmosphere containing oxygen after the resin thin film is formed.
According to another aspect of the present invention, a thin film has an interface between a resin thin film and a metal thin film which are laminated. A concentration of oxygen in the vicinity of the interface between the resin thin film and the metal thin film is higher than a concentration of oxygen in a middle portion of the resin thin film in its thickness direction.
In one embodiment of the present invention, the concentration of oxygen in the vicinity of the interface is about 1.3 times or more the concentration of oxygen in a middle portion of the resin thin film in its thickness direction.
In another embodiment of the present invention, the resin thin film contains at least one acrylate monomer.
In still another embodiment of the present invention, the resin thin film and the metal thin film are alternately laminated.
According to another aspect of the present invention, an electronic component having the above-described thin film is provided.
In one embodiment of the present invention, the thickness of the metal thin film is in a range of about 50 nm to about 2000 nm, and the thickness of the resin thin film is in a range of about 0.05 to about 3 xcexcm.
In another embodiment of the present invention, the metal thin film is a stripe-like thin film.
In still another embodiment of the present invention, the metal thin film includes a layer made of different metal materials.
In yet still another embodiment of the present invention, the thickness of the metal thin film is in a range of about 15 to about 100 nm, and a thickness of a resin thin film is in a range of about 0.05 xcexcm to about 1 xcexcm.
In still another embodiment of the present invention, an outermost layer of the resin thin film is thicker than the other resin thin film layers.
Thus, the invention described herein makes possible the advantage of: (1) providing a method and an apparatus for forming a high-quality resin thin film suitable for use as an electronic component or the like, the method requiring no solvent and thus realizing superior productivity of the thin film and environmental protection; (2) providing a method and an apparatus for forming a resin thin film having superior flatness so as to provide a high-performance electronic components; and (3) providing a method and an apparatus for forming a laminate film with strong adhesion between the film layers so as to provide a highly-reliable high-performance electronic components.
These and other advantages of the present invention will become apparent to those skilled in the art upon reading and understanding the following detailed description with reference to the accompanying figures.